Study: Virtual colonoscopy sensitivity equivalent to conventional colonoscopy

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Results from a pair of virtual colonoscopy studies published this week demonstrate that the technique works just as well at spotting potentially cancerous growths as optical colonoscopy.

According to results from the American College of Radiology Imaging Network (ACRIN), CT colonography is at least as sensitive as conventional colonoscopy in detecting adenomas 1cm in diameter or larger. Concurrently, a study published in this week’s New England Journal of Medicine (NEJM) found that virtual colonoscopy and conventional colonoscopy had similar detection rates for advanced neoplasia.

The ACRIN trial compared the detection of polyps and early-stage cancer of the colon using either conventional optical colonoscopy or CT colonography, in which images are reconstructed by computer to provide a virtual image of the colon. Patients were investigated using both procedures and the resulting CT images were read by a panel of radiologists.

The study, funded by the U.S. National Institutes of Health (NIH), was initiated in 2005 and has involved more than 2,500 asymptomatic patients aged 50 or over at 15 centers throughout the United States. Researchers reported that CT colonography achieved 90 percent sensitivity for identifying patients harboring a 1-cm adenoma.

The NEJM study, conducted at the University of Wisconsin Medical School in Madison, included 3,120 patients who opted for a virtual colonoscopy and 3,163 who chose the traditional exam.

Approximately the same number of advanced polyps were found in each group, 123 for the CT colonography group and 121 for the optical colonoscopy group. About 8 percent in the virtual colonoscopy group had same-day traditional colonoscopies for polyp removal, according to the researchers. A further 5 percent of the virtual colonoscopy patients had one or two small polyps and chose to have them watched rather than removed.